When it comes to using air tools for auto repair, many people get caught up on air tank size, but it’s crucial to understand that tank size is really just about reserve capacity. The truth is, even a small, 1-gallon compressor can operate almost any air tool. The limitation isn’t whether it can run the tool, but how long it can run it continuously before needing to refill.
I’ve personally used a 20-gallon Craftsman compressor, marketed at “5hp” (peak), which delivered around 8 CFM. This setup was capable of powering all sorts of air tools, from a heavy-duty 3/4″ impact wrench to a Dual-Action (DA) sander and even a paint gun. However, with tools that consume a lot of air, like sanders or impact wrenches used for extended periods, the compressor would struggle to keep up. You’d find yourself needing to pause work to let the pressure build back up, otherwise the tool’s performance would noticeably drop. The compressor pump would run constantly, unable to maintain pressure for continuous high-demand tasks.
Later, for my shop, I upgraded to a much larger 80-gallon, true 5hp compressor (5hp running, significantly higher peak), producing over 20 CFM. This made a world of difference. It could run any of my air tools non-stop without issue. It cycled on and off so infrequently, it was as if the air tools were barely making a dent in its capacity.
However, the advancements in cordless power tools have been remarkable. If I wasn’t operating a professional shop, I might not even bother with air tools anymore. Cordless tools offer incredible portability and are now nearly as powerful, and in some cases even more powerful than their pneumatic counterparts. The convenience of battery power, usable anywhere with a 12V source like your car or standard 110V AC at home, makes cordless tools an extremely attractive option for many automotive tasks today.
